RHIC Startup: The beam needed a chromaticity jump to +2 at injection to get good efficiency, but then -2 when the beams are brought into collision. Clearly something is wrong. We need a knob to adjust the chromaticity.
The Yellow Landau cavities are not yet on. Mike Brennan thinks that at these intensities, we would benefit from turning them on.
Without collisions, the beams are at an unstable chromaticity. Bringing the beams into collision then causes poor lifetime and large loss rates.
Problems during the maintenance day continue to plague us. The beginning of the maintenance went well, with Booster and AGS back on before noon, and PS work in testing mode, as requested. But the work on the breaker at Building 929 was initially delayed because the parts had not be delivered in time. They finally arrived at BNL at 10:30, coming to C-AD after lunch. After some discussion, it was decided that since the breaker had been performing in a stable manner for the two week period during which measurements had been taken, so we could postpone the work for two weeks, until the next maintenance day. Two hours later Jon Sanberg reported that the breaker in Building 929 had increased in temperature by 11 degrees in one day. At this point the risk of postponing the work seemed too great, and at 2:30 PM the work on replacing the breaker began. The actual breaker exchange took only about 15 minutes, but with all the end effects, we were ready to be back on by 18:00. We began with a 6x6 store which went well, then attempted a 78x78 bunch store. There was a QLI followed by another QLI. Then MMPS tripped off, and RF tripped off, followed by a couple of Permit Interlocks being pulled by Loss Monitors. It took until 6:00 AM the next morning, ~12 hours late, when we managed to put up a store following the Maintenance Day. We will have to think hard, basing our decision on data taken from all the maintenance day, day after and week after maintenance days to judge whether Maintenance Days are beneficial or not,
| Scheduling Physicist: Mike Sivertz | Last updated: 12/07/2007 16:25:28 |
| Email: sivertz@bnl.gov | |
| Office Phone: 631-344-6102 | |
| Digital Pager: 7528 or 4300 | |
| Home Phone: 631-878-9020 |